Evaluating prosthetic heart valve placement

ABSTRACT

A method for evaluating the placement of a prosthetic heart valve in a structure of interest. The method comprises acquiring one or more depictions of an anatomical region of interest that includes the structure of interest, wherein each depiction shows the structure of interest and/or the blood pool volume of the left ventricular outflow tract (LVOT) of the patient&#39;s heart. The method further comprises designating one or more positions in at least one of the one or more depictions wherein each position corresponds to a respective position in the structure of interest at which the prosthetic valve may be placed. The method still further comprises predicting, for each of the one or more designated positions, an amount of blood flow obstruction through the LVOT of the patient&#39;s heart that would occur if the prosthetic valve was to be placed at a corresponding position in the structure of interest.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/090,067 filed Dec. 10, 2014, the entire contents ofwhich are hereby incorporated by reference.

TECHNICAL FIELD

This disclosure relates generally to prosthetic heart valves, and moreparticularly to periprocedurally evaluating the placement of aprosthetic heart valve, such as, for example and without limitation, aprosthetic mitral valve, in a given structure of interest.

BACKGROUND

Non-invasive percutaneous implantation of prosthetic devices, forexample, heart valves, poses certain challenges to physicians. Asopposed to surgically invasive procedures, such as, for example, openheart surgery, physicians performing non-invasive percutaneousimplantation procedures have a limited field of view and are generallylimited to the use of images generated by two-dimensional (2D) imagingmodalities (e.g., fluoroscopy, ultrasound, etc.) during the procedure.Accordingly, periprocedural planning for non-invasive procedures thatinvolves advanced imaging strategies can lead to more successfulpercutaneous implantation outcomes.

In the field of cardiology, transfemoral, transapical, and transaorticimplantation are promising alternatives to open heart surgery,particularly for inoperable and high surgical risk patients. However,because physicians are typically limited to 2D imaging during theprocedure itself, proper planning and evaluation is required toaccurately assess and determine, for example, the placement of theprosthetic device within the structure in which the prosthetic device isbeing implanted that is ideal or optimal for that particular patient.Additionally, as it relates to transcatheter mitral valve replacement(TMVR), conventional transcatheter prosthetic heart valves are notspecifically designed for mitral position implantation and haveintrinsic geometry that may present challenges to mitral implantation.For example, such heart valves may present challenges as it relates toleft ventricular outflow tract (LVOT) obstruction.

SUMMARY

According to one embodiment, there is provided a computer-implementedmethod for evaluating the placement of a prosthetic mitral heart valvein a structure of interest located in the heart of a patient. The methodcomprises acquiring one or more depictions of an anatomical region ofinterest that includes the structure of interest, wherein each of theone or more depictions shows the structure of interest, the blood poolvolume of the left ventricular outflow tract (LVOT) of the patient'sheart, or both. The method further comprises designating one or morepositions in at least one of the one or more depictions, wherein eachposition corresponds to a respective position in the structure ofinterest at which the prosthetic valve may be placed. The method stillfurther comprises predicting, for each of the one or more positions, anamount of blood flow obstruction through the LVOT of the patient's heartthat would occur if the prosthetic valve was to be placed at acorresponding position in the structure of interest.

According to another embodiment, there is provided acomputer-implemented method for evaluating the placement of a prostheticmitral heart valve in a structure of interest located in the heart of apatient. The method comprises acquiring a depiction of an anatomicalregion of interest that includes the structure of interest, wherein thedepiction shows the structure of interest and the blood pool volume ofthe LVOT of the patient's heart. The method further comprises importingone or more models of the prosthetic valve into the acquired depictionof the structure of interest. The method still further comprisespredicting, for each of the one or more positions of the one or moremodels of the prosthetic valve, an amount of blood flow obstructionthrough the LVOT of the patient's heart that would occur if theprosthetic valve was to be placed at a corresponding position in thestructure of interest.

According to yet another embodiment there is provided acomputer-implemented method for evaluating the placement of a prostheticmitral heart valve in a structure of interest located in the heart ofthe patient. The method comprises acquiring a plurality of images of ananatomical region of interest that includes the structure of interest,wherein each of the plurality of images shows the structure of interest,the blood pool volume of the LVOT of the patient's heart, or both. Themethod further comprises designating a position in at least one of theone or more images that corresponds to a position in the structure ofinterest at which the prosthetic valve may be placed. The method stillfurther comprises predicting an amount of blood flow obstruction throughthe LVOT of the patient's heart that would occur if the prosthetic valvewas to be placed at a position in the structure of interest thatcorresponds to the position designated in the at least one of the one ormore images.

BRIEF DESCRIPTION OF DRAWINGS

One or more embodiments of the invention will hereinafter be describedin conjunction with the appended drawings, wherein like designationsdenote like elements, and wherein:

FIG. 1 is a schematic and diagrammatic view a portion of the humanheart;

FIG. 2 is a schematic and diagrammatic view of the mitral valve of ahuman heart showing the operation of the mitral valve;

FIG. 3 is a schematic and block diagram of an illustrative embodiment ofa system for performing one or more embodiments of the methodologydescribed herein;

FIG. 4 is a flowchart of an illustrative embodiment of a method that maybe used to evaluate prosthetic heart valve placement;

FIG. 5 is an computed tomography (CT) image of the aortic annulus of apatient that may be used, for example, in the performance of one or moresteps of the method illustrated in FIG. 4;

FIG. 6 is a CT image of the aortic annulus shown in FIG. 5 with a splinedisposed thereon representing the aortic annulus and a plane containingthe aortic annulus;

FIG. 7 is a CT image of the mitral annulus of a patient that may beused, for example, in the performance of one or more steps of the methodillustrated in FIG. 4, wherein the image has a spline disposed thereonrepresenting the mitral annulus and a plane containing the mitralannulus;

FIG. 8 is CT image of a portion of a previously-implanted prostheticmitral valve that may be used, for example, in the performance of one ormore steps of the method illustrated in FIG. 4, wherein he image showsmarkers or landmarks that may be used for performing the method;

FIG. 9 is a CT image of the mitral annulus that may be used, forexample, in the performance of one or more steps of the methodillustrated in FIG. 4, wherein the image has a spline disposed thereonrepresenting the mitral annulus and a plane containing the mitralannulus;

FIGS. 10a-10e are depictions of models that may be used in theperformance of the method illustrated in FIG. 4, and showing anillustrative embodiment of how the method illustrated in FIG. 4 iscarried out;

FIGS. 11a-11e are depictions of models that may be used in theperformance of the method illustrated in FIG. 4, and showing anillustrative embodiment of how the method illustrated in FIG. 4 iscarried out;

FIGS. 12a-12d are depictions of models that may be used in theperformance of the method illustrated in FIG. 4, and showing anillustrative embodiment of how the method illustrated in FIG. 4 iscarried out;

FIG. 13 is a flowchart of another illustrative embodiment of a methodthat may be used to evaluate prosthetic heart valve placement; and

FIGS. 14a-14c are images that may be used in the performance of themethod illustrated in FIG. 13, and showing an illustrative embodiment ofhow the method illustrated in FIG. 13 is carried out.

DETAILED DESCRIPTION

The system and method described herein can assist physicians inpre-operational planning and post-operative evaluation (also referred toas “periprocedural planning”) of percutaneous procedures, for example,procedures involving the implantation of prosthetic heart valves.Generally, the system and method described herein use advanced imagingand modeling strategies to accurately assess the placement orpositioning of a prosthetic valve in a structure of interest, and todetermine an ideal or optimal position of the prosthetic valve in thestructure of interest that is specific to the particular patient onwhich the procedure is to be performed. Although the system and methodmay be applicable to planning for and evaluating a variety ofprocedures, they are particularly applicable to procedures involving themitral heart valve, and the implantation of a prosthetic mitral valve,in particular. Accordingly, the description below will be primarily withrespect to the evaluation of the placement of a prosthetic mitral valve.It will be appreciated, however, that various teachings set forth hereincould also be applied to any number of other procedures, and thus, thepresent disclosure is not intended to be limited to the use of thesystem and method described herein for any particular type(s) ofprocedure(s).

For purposes of context, FIGS. 1 and 2 depict a native mitral valve 10.The mitral valve 10 is disposed between the left atrium (not shown) andthe left ventricle 12, and is configured to control or regulate theblood flow from the left atrium to the left ventricle. Morespecifically, as the mitral valve opens, an asymmetric toroidal vortexforms during the early diastolic phase of the cardiac cycle as bloodflows from the left atrium to the left ventricle. The unique saddleshape of the annulus 14 of the mitral valve 10 changes during thecardiac cycle, and is at its largest in the diastolic phase when thevalve is open, and is at its smallest in the systolic phase when thevalve is closed. Unlike the aortic valve which is gated by threeleaflets, the mitral valve is gated by two leaflets: an anterior leaflet16 and a posterior leaflet 18. In at least some embodiments, determiningan optimal or ideal placement of a prosthetic mitral valve requires anaccurate evaluation or assessment of the annulus 14 (also referred toherein as “mitral annulus”).

FIG. 3 depicts an illustrative embodiment of a system 20 for evaluatingthe placement of a prosthetic device in a structure of interest locatedin an anatomical region of interest of a patient's body. In anembodiment, the prosthetic device is a prosthetic heart valve (e.g., aprosthetic mitral valve) and the anatomical region of interest is atleast a region of the patient's heart. In the illustrative embodiment,the system 20 comprises, among potentially one or more other components,an electronic control unit (ECU) 22, a display device 24, and one ormore user interface devices 26.

The ECU 22 may comprise one or more electronic processing units 28 andone or more electronic memory devices 30, as well as, for example,input/output (I/O) devices and/or other known components. In anotherembodiment, rather than the ECU 22 comprising the memory device 30, thesystem 20 may include one or more memory devices 30 that are separateand distinct from the ECU 22 (and the processing unit(s) 28 thereof, inparticular) but that is/are accessible thereby.

The processing unit(s) 28 of the ECU 22 may include any type of suitableelectronic processor (e.g., a programmable microprocessor ormicrocontroller, an application specific integrated circuit (ASIC),etc.) that is configured to execute appropriate programming instructionsfor software, firmware, programs, algorithms, scripts, etc., to performvarious functions, such as, for example and without limitation, one ormore steps of the methodology described herein.

The memory device(s) 30, whether part of the ECU 22 or separate anddistinct therefrom, may include any type of suitable electronic memorymeans and may store a variety of data and information. This includes,for example, software, firmware, programs, algorithms, scripts, andother electronic instructions that, for example, are required to performor cause to be performed one or more of the functions describedelsewhere herein (e.g., that are used (e.g., executed) by ECU 22 (andthe processing unit(s) 28 thereof, in particular) to perform variousfunctions described herein). Alternatively, rather than all of theaforementioned information/data being stored in a single memory device,in an embodiment, multiple suitable memory devices may be provided.These are, of course, only some of the possible arrangements, functionsand capabilities of ECU 22, as others are certainly possible. In anyevent, in at least some embodiments, the memory device 30 may comprise acomputer program product, or software, that may comprise or include anon-transitory, computer-readable storage medium. This storage mediummay have instructions stored thereon that may be used to program acomputer system (or other electronic devices, for example, the ECU 22)to implement the control of some or all of the functionality describedherein. A computer-readable storage medium may include any mechanism forstoring information in a form (e.g., software, processing application)readable by a machine (e.g., a computer, processing unit, etc.). Thecomputer-readable storage medium may include, but is not limited to,magnetic storage medium (e.g., floppy diskette); optical storage medium(e.g., CD-ROM); magneto optical storage medium; read only memory (ROM);random access memory (RAM); erasable programmable memory (e.g., EPROMand EEPROM); flash memory; or electrical or other types of mediumsuitable for storing program instructions. In addition, programinstructions may be communicated using optical, acoustical, or otherform of propagated signal (e.g., carrier waves, infrared signals,digital signals, or other types of signals or mediums).

The display device 24 may comprise any number of display devices knownin the art, for example and without limitation, liquid crystal display(LCD), cathode ray tube (CRT), plasma, or light emitting diode (LED)monitors or displays. The display device 24 is electrically connected orcoupled to the ECU 22 and is configured to be controlled by the ECU 22such that images or models of, for example, anatomical structuresgenerated or obtained by the ECU 22, including those used in performingthe method described below, may be displayed thereon and may be used forthe purposes described herein. Additionally, in an embodiment whereinthe ECU 22 may be configured to generate an interactive graphical userinterface (GUI) that allows, for example, a physician to manipulateimages or models displayed on the display device (e.g., removing layersof a model, moving models, etc.), facilitate the taking of measurements,etc., the display device 24 may also display such a GUI. In any event,the display device 24 is configured to receive electrical signals fromthe ECU 22 and to display content represented by the received signalswhich may be viewed by, for example, a physician.

The user interface device(s) 26 may comprise any number of suitabledevices known in the art. For example, and without limitation, the userinput device(s) 26 may comprise one or a combination of a touch screen(e.g., LCD touch screen), a keypad, a keyboard, a computer mouse orroller ball, and/or a joystick, to cite a few possibilities. In certainimplementations, the display device 24 and user input device 26 may becombined together into a single device. Regardless of the particularform the user interface device(s) take, the user input device(s) 26 maybe electrically connected or coupled (e.g., via wired or wirelessconnections) to the ECU 22, and are configured to facilitate a measureof communication between a user (e.g., physician) and the system 20, andthe ECU 22 thereof, in particular. More particularly, the user interfacedevice(s) 26 may allow a physician to manipulate images or modelsdisplayed on the display device 24 (e.g., rotate images/models, stripaway or add layers to a model/image, move models relative to each other,import one model/image into another model/image, section portions of amodel/image, etc.), to take or command the taking of desiredmeasurements of anatomical structures represented by or in the images ormodels displayed on the display device 24, etc.

While certain components of the system 20 have been described above, itwill be appreciated that in some implementations, the system 20 mayinclude more or fewer components than are included in the arrangementdescribed above. Accordingly, the present disclosure is not intended tobe limited to any particular implementation(s) or arrangement(s) of thesystem 20.

Turning now to FIG. 4, there is shown an illustrative embodiment of amethod (method 100) for evaluating the placement of an implantableprosthetic device within a structure of interest located an anatomicalregion of a patient's body. The prosthetic device may be, for example, aprosthetic heart valve, and in an embodiment, a prosthetic mitral heartvalve; and thus, in an embodiment, the anatomical region in which thestructure of interest is located may at least partially include thepatient's heart (or at least a portion thereof, for example, one or moreof the left ventricle, the left atrium, and the LVOT of the patient'sheart). For purposes of illustration, the description below will beprimarily with respect to evaluating the placement of a prostheticmitral heart valve. It will be appreciated, however, that themethodology described herein may be used to evaluate the placement ofother prosthetic devices.

In at least some embodiments, all of the steps of method 100 may beperformed or carried out by an appropriately or suitably configuredsystem, for example and without limitation, the system 20 describedabove, either alone or in conjunction with input from a user (e.g.,physician). In other embodiments, however, some, but not all, of thesteps may be performed or carried out by different systems such thatcertain steps may be performed by one system (e.g., system 20), andother steps may be performed by one or more other suitable systems. Forpurposes of illustration, the description below will be primarily withrespect to an embodiment wherein the method 100 is performed by thesystem 20 described above either alone or in conjunction with userinput. It will be appreciated, however, that the present disclosure isnot limited to such an embodiment. Additionally, it will be appreciatedthat unless otherwise noted, the performance of method 100 is not meantto be limited to any one particular order or sequence of steps, or toany particular component(s) for performing the steps.

In an embodiment, method 100 includes a step 102 of defining a planethat contains the aortic annulus of the patient's heart, hereinafterreferred to as the “aortic plane.” Step 102 may be performed using anynumber of techniques known in the art. In one embodiment, however, step102 comprises acquiring image data relating to an anatomical region ofthe patient's heart that includes at least portions of the leftventricle, left atrium, and aorta of the patient's heart. In anillustrative embodiment, the image data comprises computed tomography(CT) image data, and more particularly, two-dimensional (2D) CT data. Itwill be appreciated, however, that in other embodiments, the image datamay comprise data acquired using an imaging modality other than CT, forexample, magnetic resonance imaging (MRI), echocardiogram imaging, oranother suitable imaging modality. Accordingly, the present disclosureis not intended to be limited to any particular type of image data;however, for purposes of illustration and clarity, the description belowwill be primarily with respect to an embodiment wherein CT image data isused. Additionally, in an embodiment, image data may be acquired forboth the diastolic and systolic phases of the patient's cardiac cycle,and in such as embodiment, the aortic plane may be defined for eachphase.

In any event, in an embodiment, one or more 2D images or views generatedor produced from the acquired CT image data may be used to define theaortic plane. More particularly, a 2D image may be used to define acertain number of points (e.g., three (3) points) that may be used todefine the aortic plane. In an embodiment, one or more predeterminedlandmarks (e.g., anatomical landmarks) may be used to define theplane-defining points. In one such embodiment, the predeterminedlandmarks may comprise the cusps of the aortic valve. FIG. 5 depicts a2D CT image in which three points 32 a, 32 b and 32 c each correspondingto an aortic valve cusp are defined. Regardless of the landmarks used,the plane-defining points may be defined or identified in a number ofways. In one embodiment, the points may be defined automatically by theECU 22 of the system 20 (e.g., by the processing unit 28 of the ECU 22)using suitable image processing software/techniques. In otherembodiments, the points may be defined by a user (e.g., physician). Morespecifically, the 2D image may be displayed on the display device 24 andthe user may define the plane-defining points using the user interfacedevice(s) 26 of the system 20. For example, the user may manipulate amouse device to move a cursor to a desired location in the displayedimage and to “click” the mouse to define a point. In any event, once theplane-defining points are defined, a plane containing all of the definedpoints can be defined as the aortic plane. In at least some embodiments,the aortic plane can be represented on a 2D image by a spline 34representative of the aortic annulus, which may be displayed on thedisplay device 24 as shown in FIG. 6. While certain techniques orimplementations for defining the aortic plane-defining points, and thus,defining the aortic plane itself have been provided above, it will beappreciated that any suitable technique(s) for doing so may be used.Accordingly, the present disclosure is not intended to be limited to anyparticular technique(s) for doing so.

In an embodiment, the method 100 further includes a step 104 of defininga plane that contains the mitral annulus of the patient's heart,hereinafter referred to as the “mitral plane.” As with step 102, step104 may be performed using any number of techniques known in the art.For example, in one embodiment, step 104 comprises acquiring image datarelating to an anatomical region of the patient's heart that includes atleast portions of the left ventricle, left atrium, and aorta of thepatient's heart. This image data may be the same image data acquired instep 102 or may comprise different image data. In either instance, theimage data may comprise CT image data, and more particularly, 2D CTdata. It will be appreciated, however, that in other embodiments, theimage data may comprise data acquired using an imaging modality otherthan CT, for example, MRI, echocardiogram, or another suitable imagingmodality. Accordingly, the present disclosure is not intended to belimited to any particular type of image data; however, for purposes ofillustration and clarity, the description below will be primarily withrespect to an embodiment wherein CT image data is used. Additionally, inan embodiment, image data may be acquired for both the diastolic andsystolic phases of the patient's cardiac cycle, and in such asembodiment, the mitral plane may be defined for each phase.

In any event, in an embodiment, one or more 2D images generated from theacquired CT image data may be used to define the mitral plane. Moreparticularly, a 2D image may be used to define a certain number ofpoints (e.g., three (3) points) that may be used to define the mitralplane. In an embodiment, one or more predetermined landmarks (e.g.,anatomical landmarks) may be used to define the plane-defining points.The particular landmarks used may depend, at least in part, on thenature of the structure of interest into which the prosthetic valve isto be implanted. For example, in an instance wherein the structure ofinterest is a native mitral valve, the landmarks may include areas ofcalcification and/or leaflet tips and/or insertion points at the mitralannulus of the native valve, to cite few possibilities. In an instancewherein the structure of interest comprises a previously-implanteddevice or object, for example, a mitral ring, the landmarks may comprisethat device or at least certain portions thereof. An example of such aninstance is shown in FIG. 7 wherein a previously-implanted mitral ring36 is shown in a 2D CT image. Finally, in an instance wherein thestructure of interest comprises a previously-implanted prosthetic mitralvalve (i.e., for a “valve-in-valve” procedure wherein a secondprosthetic valve is implanted within a first, previously-implantedprosthetic valve), the landmarks may comprise portions of thepreviously-implanted valve, for example, the tips of the struts of thepreviously-implanted valve. An example of this instance is shown in FIG.8, which depicts a 2D CT image in which three points 38 a, 38 b and 38c, each corresponding to a strut tip of a previously-implantedprosthetic mitral valve, are defined. In any event, the plane-definingpoints may be defined or identified in a number of ways. In oneembodiment, the points may be defined automatically by the ECU 22 of thesystem 20 (e.g., by the processing unit 28 of the ECU 22) using suitableimage processing software/techniques. In other embodiments, the pointsmay be defined by a user (e.g., physician). More specifically, the 2Dimage may be displayed on the display device 24 and the user may definethe plane-defining points using the user interface device(s) 26 of thesystem 20. For example, the user may manipulate a mouse device to move acursor to a desired location in the image and to “click” the mouse todefine a point. In any event, once the plane-defining points aredefined, a plane containing all of the defined points can be defined asthe mitral plane. In at least some embodiments, the mitral plane can berepresented on a 2D image by a spline 40 representative of the mitralannulus, which may be displayed on the display device 24 as shown inFIG. 9. While certain techniques or implementations for defining themitral plane-defining points, and thus, defining the mitral plane itselfhave been provided above, it will be appreciated that any suitabletechnique(s) for doing so may be used. Accordingly, the presentdisclosure is not intended to be limited to any particular technique(s)for doing so.

In an embodiment, the performance of steps 102 and 104 may befacilitated at least in part by software stored in, for example, thememory device 30 of the system 20. In an embodiment, this software maycomprise a software program commercially available from Materialise NVunder the name Mimics®; though any other suitable software may certainlybe used instead. In an embodiment, each of the defined aortic and mitralplanes (i.e., the splines 34, 40 representative thereof, respectively)may be exported as, for example, an .IGES file, and may be used as willbe described below.

Once the aortic and mitral planes are defined in steps 102 and 104,respectively, method 100 may comprise a step 106 of acquiring one ormore depictions of an anatomical region of interest of the patient'sbody that includes the structure of interest, and wherein each of theone or more depictions shows the structure of interest, the blood poolvolume of the left ventricular outflow tract (LVOT) of the patient'sheart, or both. In an embodiment, the one or more depictions compriseone or more computer-generated models of the anatomical region ofinterest, for example, one or more three-dimensional (3D) models. Forpurposes of illustration and clarity, the description below will be withrespect to an embodiment wherein the acquired depiction(s) comprise a 3Dmodel of the anatomical region of interest showing the structure ofinterest and the blood pool volume of the LVOT. It will be appreciated,however, that in other embodiments, multiple depictions in the form oftwo or more computer-generated models each showing the structure ofinterest, the LVOT blood pool volume, or both may be acquired and usedin the manner to be described below.

In an embodiment where a single 3D model is acquired in step 106, thatmodel may be acquired in a number of ways. One way is by obtaining apreviously-generated model from a memory device, for example, the memorydevice 30 of the system 20. Another way is by generating the model fromimage data, for example 2D image data. In the latter instance, the imagedata may be the same image data acquired in step 102 and/or step 104, oralternatively, may be other image data (e.g., 2D CT image data) acquiredas part of step 106. In either instance, the model may be generatedusing techniques well known in the art, such as, for example, that orthose techniques described in U.S. patent application Ser. No.14/820,617 filed on Aug. 7, 2015, the entire contents of which areincorporated herein by reference; and in an embodiment, may be generatedby, for example, the ECU 22 of the system 20, and the processing unit 28thereof, in particular. Accordingly, it will be appreciated that thepresent disclosure is not intended to be limited to any particularway(s) of acquiring the one or more depictions in step 106.

Regardless of how the one or more depictions is/are acquired in step106, in an embodiment, the acquired depictions (e.g., the single 3Dmodel) may be copied into or used by a suitable software program forperforming the steps below. An example of such software is thatcommercially available from Materialise NV under the name 3-Matic STL.Representations of the aortic and mitral planes defined respectively insteps 102 and 104 may also be imported into the model acquired in step106.

To better illustrate, FIG. 10a depicts a portion of a model 41 acquiredin step 106 that includes or shows a model of a structure of interest 42in the nature of a previously-implanted mitral ring, along withrepresentations 43, 44 of the aortic and mitral planes, respectively(which, in an embodiment, may comprise splines 34, 40 representing theaortic and mitral planes, respectively). As shown in FIG. 10a , in anembodiment, the splines 34, 40 representing the aortic and mitral planesmay have datum planes fit to the origins thereof using, for example, a“fit plane” operation to define or generate the representations 43, 44of the aortic and mitral planes. It will be appreciated that in anembodiment, the model 41 may also show or include a model of the LVOTblood pool volume. In at least certain embodiments, the blood poolvolume portion of the model 41 may be “hidden” such that it is notalways visible, which is the case in the embodiment shown in FIG. 10 a.

FIG. 11a also depicts an embodiment wherein at least a portion of amodel 46 acquired in step in step 106 that includes or shows a model ofa structure of interest 48 in the nature of a previously-implantedprosthetic mitral valve, along with representations 43, 44 of the aorticand mitral planes (which, in an embodiment, may comprise splines 34, 40representing the aortic and mitral planes, respectively). As with FIG.10a described above, it will be appreciated that in an embodiment, themodel 46 may also show or include a model of the LVOT blood pool volume.In at least certain embodiments, the blood pool volume portion of themodel 46 may be “hidden” such that it is not always visible, which isthe case in the embodiment shown in FIG. 11 a.

In any event, in at least some implementations, the placement of therepresentations of the aortic and mitral planes relative to the acquiredmodel is controlled entirely by the software program, and the locationsat which the representations are placed correspond at least generally tothe actual locations of the aortic and mitral annuli of the patient'sheart relative to the structure of interest and/or the LVOT of thepatient's heart. Additionally, in at least some implementations, atleast a portion of the model acquired in step 106 and therepresentations 43, 44 of one or both of the aortic and mitral planesmay be displayed on, for example, the display device 24 of the system20, for a user of the system 10 to view.

In an embodiment, following the acquisition of depiction(s) step 106 andthe incorporation of the representations 43, 44 of the aortic and mitralplanes therewith, method 100 may move to a step 108 of designating oneor more positions in at least one of the acquired depictions (e.g., 3Dmodel) showing the structure of interest, wherein each designatedposition corresponds to a respective position or location in thestructure of interest at which the prosthetic valve may be placed. In anembodiment, step 108 comprises importing one or more models or otherrepresentations of a prosthetic valve into the one or more acquireddepictions showing the structure of interest, and placing each of theone or more imported model(s) at respective positions within thestructure of interest shown in the depiction(s). For purposes of thisdisclosure, and as will be described more fully below, a “position”within the structure of interest shown in the acquired depiction(s) isintended to connote an axial position relative to an axis that, in atleast some embodiments, is perpendicular to the mitral plane, and/or anorientation relative to an axis that is, in at least some embodiments,perpendicular to the mitral plane.

To better illustrate, FIG. 10b depicts the model 41 that includes orshows the model 42 of a previously-implanted mitral ring, and an axis 50that in this example extends perpendicular to the representation of themitral plane 44. A computer-generated valve model 52 is imported intothe model 41 and placed at a particular axial position within the mitralring model 42, which, in this particular illustration, is the “50/50”valve position meaning that approximately 50% of the valve model isdisposed on either side of the mitral ring model 42, and thus,approximately 50% of the valve would extend into each of the left atriumand left ventricle.

Similarly, in FIG. 11b depicts the model 46 that includes or shows themodel 48 of a previously-implanted prosthetic mitral valve, and an axis54 that in this example extends perpendicular to a representation of themitral plane 44. A computer-generated valve model 56 is imported intothe model 46 and placed at a particular axial position within the model48 of the previously-implanted prosthetic valve. In this illustration,the mitral plane 44 is offset to the bottom of the model 48 and definesa 0% position meaning that no part of the valve model extends beyond theboundary of the model 48. The valve model 56 is then aligned with theoffset mitral plane 44 such that it assumes the 0% position.

In any event, the placement of the valve model imported in step 108 maybe controlled entirely by the software program using a plane-to-planealign tool/operation wherein the mitral plane is used as the fixedentity and a portion of the valve model is used as the moving entity. Itwill be appreciated, however, that other ways of placing the valve modelmay certainly be used instead, including manually by a user using theuser interface device(s) 26 of the system 20.

In an embodiment, following the importation of a valve model in step108, method 100 may proceed to one or more subsequent steps, such as,for example, step 110 described below. In such an embodiment, step 108,and in some embodiments, steps 106 and 108 may thereafter be repeated toevaluate a different position within the model of the structure ofinterest. Alternatively, in other embodiments, step 108 may be repeatedany number of times to import one or more additional valve models intothe model of the structure of interest wherein each valve model isplaced at a different position prior to method 100 moving to asubsequent step.

By way of illustration, FIG. 10c depicts an embodiment wherein step 108was performed five (5) times to import five (5) different valve models52 (i.e., valve models 52 a-52 e) into the model 42 of the structure ofinterest (i.e., model of a previously-implanted mitral ring). FIG. 10calso shows or includes a model 58 of a portion of the LVOT blood poolvolume. As shown, each valve model 52 is disposed at a different axialposition relative to the axis 50. For example, a first valve model 52 amay be disposed at the 50/50 position described above with respect toFIG. 10b ; a second valve 52 b model may be disposed at a positionwhereat the valve extends 10% further into the left ventricle from the50/50 position (i.e., the “60/40” position); a third valve model 52 cmay be disposed at a position whereat the valve extends 20% further intothe ventricle from the 50/50 position (i.e., the “70/30” position); afourth valve model 52 d may be disposed at a position whereat the valveextends 10% further into the left atrium from the 50/50 position (i.e.,the “40/60” position); and a fifth valve model 52 e may be disposed at aportion whereat the valve extends 20% further into the atrium from the50/50 position (i.e., the “30/70” position). As can be seen in FIG. 10c, in an embodiment, the valve models 52 may be placed in theircorresponding positions using markers or indicators on the valve models52. For example, each valve model 52 may have markers or indicatorscorresponding to the 50/50, 60/40, 70/30, etc. positions. When it isdesired to place a valve model at a particular position, thecorresponding marker on the valve model is aligned with therepresentation 44 of the mitral plane.

FIG. 11c depicts an embodiment wherein step 108 was performed three (3)times to import three (3) different valve models 56 (i.e., valve models56 a-56 c) into the model 48 of the structure of interest (i.e., modelof a previously-implanted prosthetic valve). FIG. 11c also shows orincludes a model 60 of a portion of the LVOT blood pool volume. Asshown, each valve model 56 is disposed at a different axial positionrelative to the axis 54. For example, a first valve model 56 a may bedisposed at the 0% position described above with respect to FIG. 11b ; asecond valve model 56 b may be disposed at a position whereat the valveextends 10% further into the left ventricle from the 0% position; and athird valve model 56 c may be disposed at a position whereat the valveextends 20% further into the ventricle from the 0% position (i.e., 10%further than the 10% position). As discussed above with respect to FIG.10c , the valve models 56 may be placed in their corresponding positionsusing markers or indicators on the valve models 52. When it is desiredto place a valve model at a particular position, the correspondingmarker on the valve model is aligned with the representation 44 of themitral plane that was offset to the bottom of the model 48.

Accordingly, it will be appreciated that any number of valve models maybe imported in step 108, and that those valve models may be placed anynumber of different axial positions within the model of the structure ofinterest, including, but certainly not limited to, those describedabove. In any event, in an embodiment wherein step 108 is repeated oneor more times before method 100 proceeds to a subsequent step, method100 would proceed to a subsequent step only once the desired number ofvalve models have been imported and placed in the model of the structureof interest.

While the description of step 108 has thus far been with respectdesignating one or more hypothetical valve positions in terms of axialposition(s) of one or more valve models within the depiction of thestructure of interest, step 108 may additionally or alternativelycomprise designating one or more positions in terms of the angularorientation of one or more valve models within the depiction of thestructure of interest. More particularly, whereas each of the valvemodels 52 (i.e., 52 a-52 f) in FIG. 10c and the valve models 56 (i.e.,56 a-56 c) in FIG. 11c are coaxially arranged relative to the respectiveaxes 50, 54, in other embodiments, step 108 may comprise placing one ormore valve models in such way that the valve model(s) are not allcoaxially arranged, but rather one or more of the valve models may havea different angular orientation than one or more of the other valvemodels. In such an embodiment, the valve models may be placed at thesame axial position or at one or more different axial positions,depending on the implementation.

To better illustrate, reference is made to FIGS. 12a and 12b . FIG. 12adepicts a model 62 of a structure of interest and an axis 64 that inthis example extends perpendicular to a representation 44 of the mitralplane. A computer-generated valve model 66 is imported into the model 62and placed at a particular axial position therein. FIG. 12b depicts anembodiment wherein step 108 was performed three (3) times to importthree (3) different valve models 66 (i.e., valve models 66 a-66 c) intothe model 62 of the structure of interest. As illustrated in FIG. 12b ,each valve model 66 is disposed at a different angle relative to theaxis 64 and each other. For example, a first valve model 66 a may bedisposed at approximately a zero degree angle relative to the axis 64; asecond valve model 66 b may be disposed at a first non-zero anglerelative to the axis 64; and a third valve model 66 c may be disposed ata second non-zero angle relative to the axis 64 that is different thanthe first non-zero angle.

Accordingly, it will be appreciated that the designation in step 108 ofone or more “positions” in one or more depictions acquired in step 106may take any number of forms, and therefore, the present disclosure isnot intended be limited any particular form(s). Additionally, in anembodiment, step 108 may be performed automatically by, for example, theECU 22 of system 20. In other embodiments, however, step 108 may be atleast partially performed manually by a user. For example, the modelacquired in step 106 may be displayed on the display device 24 of system20 and a user may use the user interface device(s) 26 to command theimportation of a valve model and to move the valve model into a desiredposition. Accordingly, the present disclosure is not intended to belimited to any particular way(s) of performing step 108.

Following step 108, method 100 may progress to a step 110 of predicting,for each of the positions designated in step 108 (e.g., axial positions,angular orientations, or both), an amount of blood flow obstructionthrough the LVOT of the patient's heart that would occur if theprosthetic valve was actually placed at a corresponding position in theactual structure of interest. For purposes of this disclosure, the term“corresponding,” as it relates to a corresponding position in the actualstructure of interest, is intended to include instances where theposition in the actual structure of interest is exactly the same as thedesignated position in the depiction(s), or and instances where thepositions are not exactly the same but are nonetheless within aparticular tolerance (e.g., distance, angle, etc.) deemed suitable oracceptable by those of ordinary skill in the art for accuratelyperforming the methodologies described herein. As will be described morefully below, for a given valve position designated in step 108, step 110may comprise determining a cross-sectional surface area of the bloodpool volume of the LVOT corresponding to that designated position, andpredicting the blood flow obstruction through the LVOT based at least inpart on that determined cross-sectional surface area.

In an embodiment, such as that described above wherein step 106comprises acquiring a 3D model showing the structure of interest and theLVOT blood pool volume, and step 108 comprises importing one or morevalve models into that model of the structure of interest, step 110comprises predicting, for each of the valve model positions (e.g., axialpositions, angular orientations, or both), an amount of blood flowobstruction through the LVOT of the patient's heart that would occurwhen the prosthetic valve is actually placed at a corresponding positionin the actual structure of interest. In one illustrative embodiment, theperformance of step 110 for a given valve model position may comprise anumber of substeps.

More particularly, in a substep 112, a representation of the aorticplane may be offset to a point in the acquired model at which thecorresponding valve model intersects the blood pool volume. In anembodiment, this point comprises the furthest point into the blood poolvolume model that the valve model reaches. By way of illustration, FIG.10c illustrates an embodiment wherein the structure of interest is apreviously-implanted mitral ring, and five valve models 52 have beenimported into the model 42 of the mitral ring. For each position of thefive valve models, a representation of the aortic plane 43 is offset toa point at which the corresponding valve model 52 intersects the bloodpool volume model 58. As seen in FIG. 10c , the intersection point inthis particular example for a given valve model is the bottom edge ofthe valve model closest to the original representation of the aorticplane 43, and thus the aortic annulus. FIG. 11c similarly illustratessubstep 112 for an embodiment wherein the structure of interest is apreviously-implanted prosthetic valve represented by reference numeral48; and FIG. 12b also similarly illustrates substep 112 for anembodiment wherein imported valve models 66 are arranged at differentangles.

Once a representation of the aortic plane is offset as described abovefor the given valve model position being evaluated, a substep 114 ofstep 110 comprises sectioning or cutting the acquired model, and theblood pool volume shown therein, in particular, along the offset aorticplane. The cross-sectional surface area of the blood pool volume alongthe offset representation (i.e., the “cut line”) is then determined in asubstep 116. In an embodiment, one or both of substeps 114, 116 may beperformed automatically by, for example, the ECU 22 of system 20. Inother embodiments, however, one or both of the substeps may be at leastpartially performed manually by a user. For example, once the model issectioned or cut in substep 114, substep 116 may comprise rotating thecut volume so that the cross-sectional surface or cut surface can beseen on, for example, the display device 24 of the system 20, and maythen comprise manually selecting the surface for which the surface areais to be determined using, for example, the user interface device(s) 26of the system 20. The surface area may then be automatically determined(e.g., calculated) by the ECU 22 of the system 20.

In any event, it will be appreciated that the cross-sectional surfacealong the cut line for which the surface area is to be determined willinclude both the cross-sectional surface of the blood pool volume and aportion of the surface of the valve model disposed between the mitralplane and the LVOT. Accordingly, in an embodiment, step 110 may furtherinclude a substep (not shown) that may be performed prior to substep 116and that includes sectioning or cutting the acquired model along themitral plane. In any event, the surface area determined in substep 116is considered to be the “unobstructed” surface area of the LVOT bloodflow volume or the surface area “without a prosthetic valve,” and willbe referred to below as the “first surface area.” As will be describedbelow, the obstruction of the blood flow through the LVOT caused by theprosthetic valve being placed in a corresponding position within thestructure of interest can be predicted based at least in part on thisfirst, unobstructed surface area. Each of FIGS. 10d, 11d, and 12cillustrate examples of the performance of substeps 114, 116 of step 110,with FIG. 10d illustrating an embodiment wherein the structure ofinterest is a previously-implanted mitral valve, FIG. 11d is embodimentwherein the structure of interest is a previously-implanted prostheticheart valve, and FIG. 12c is an embodiment wherein the valve modelsimported into the model acquired in step 106 are arranged at differentangles.

Following the determination of the first, unobstructed surface area insubstep 116, step 110 may comprise a further substep 118 of removing theone or more valve models that were previously-imported into the acquiredmodel using, for example, Boolean subtraction, and then determining in asubstep 120 a second cross-sectional surface area of the surface alongthe cut line. Because the valve model(s) were removed from the acquiredmodel, the surface along the cut line will include only thecross-sectional surface of the blood pool volume, and the surface areaof this surface is considered to be the “obstructed” surface area or thesurface area “with a prosthetic valve.” Each of FIGS. 10e, 11e, and 12dillustrate examples of the performance of substeps 118,120 of step 110,with FIG. 10e illustrating an embodiment wherein the structure ofinterest is a previously-implanted mitral valve, FIG. 11e is embodimentwherein the structure of interest is a previously-implanted prostheticheart valve, and FIG. 12d is an embodiment wherein the valve modelsimported into the model acquired in step 106 are arranged at differentangles.

In an embodiment, one or both of substeps 118, 120 may be performedautomatically by, for example, the ECU 22 of system 20. In otherembodiments, however, substeps 118, 120 may be at least partiallyperformed manually by a user. For example, as it relates to substep 118,the model may be displayed on the display device 24 of system 20 and auser may use the user interface device(s) 26 to select the portions ofthe model to be removed (e.g., the valve models), and to then commandthat that or those portions be removed. As it relates to substep 120, auser may manually select the surface for which the surface area is to bedetermined using, for example, the user interface device(s) 26 of thesystem 20. The surface area may then be automatically determined (e.g.,calculated) by the ECU 22 of the system 20. Accordingly, the presentdisclosure is not intended to be limited to any particular way ofperforming substeps 118, 120.

In any event, the obstruction of the blood flow through the LVOT causedby the prosthetic valve being placed in a corresponding position withinthe structure of interest can be predicted based at least in part on thesecond determined surface area. In an embodiment, however, theobstruction can be predicted based on both the first and seconddetermined surface areas by subtracting the second surface area (i.e.,surface area “with prosthetic valve”) from the first surface area (i.e.,surface area “without prosthetic valve”), and dividing the result by thefirst surface area. The result is a percentage representing the amountof the LVOT that would be obstructed, and thus, the amount of blood flowobstruction through the LVOT that would be caused for a given valveposition.

In an embodiment, prior to removing the valve model(s) in substep 118,step 110 may comprise a substep of duplicating or copying the modelhaving the valve model(s) disposed therein to create a second model, andthen performing substeps 118, 120 using the second model. Both of themodels may then be saved for future use such that models showing thefirst and second cross-sectional areas are maintained.

In an instance wherein multiple valve models have been imported into themodel acquired in step 106, and thus, multiple positions are beingevaluated, the step 110 may be performed for each valve positionone-at-a-time such that the obstruction prediction is performed onevalve position at a time. In such an instance, separate models may beused for each iteration of step 110. Alternatively, each substep of step110 may be performed for each valve position before moving on to thenext substep such that step 110 as a whole is performed only once. Insuch an instance, separate models may be used for each valve positionbeing evaluated.

In any event, once each of the one or more positions designated in step108, or at least a certain number of that or those positions, have beenevaluated, and an obstruction prediction for each relevant position hasbeen made in step 110, method 100 may proceed to a step 122 ofdetermining a position or location in the structure of interest at whichto actually place the prosthetic device based at least in part of thepredicted blood flow obstruction(s).

In an embodiment, once steps 102-122 have been performed for one of thediastolic and systolic phases of the cardiac cycle, method 100 may berepeated for other of the diastolic and systolic phases, and thepredictions from step 110 and/or determinations from step 122 may beused together to determine an optimal position (i.e., axial positionand/or orientation) to place a prosthetic for that particular patient.

In addition to the above, knowing the cross-sectional surface area ofthe blood pool volume of the LVOT (i.e., the second, obstructed surfacearea discussed above) when a prosthetic valve is at a particularlocation or position within a structure of interest may also allow forthe determination or evaluation of other parameters of interest. Forexample, if a patient's stroke volume information is also available, theincrease in peak velocity (cm/sec) that the LVOT will experience withthe prosthetic valve in place can be determined by dividing the stokevolume (ml/sec) by the LVOT area (mm²).

With reference to FIG. 13, another illustrative embodiment of a method(method 200) for evaluating the placement of an implantable prostheticdevice within a structure of interest located an anatomical region of apatient's body is shown. As with the embodiment described above (i.e.,method 100), the prosthetic device may be, for example, a prostheticheart valve, and in an embodiment, a prosthetic mitral heart valve; andthus, in an embodiment, the anatomical region in which the structure ofinterest is located may at least partially include the patient's heart(or at least a portion thereof, for example, one or more of the leftatrium, left ventricle, aorta, and LVOT of the patient's heart). Forpurposes of illustration, the description below will be primarily withrespect to evaluating the placement of a prosthetic mitral heart valve.It will be appreciated, however, that the methodology described hereinmay be used to evaluate the placement of other prosthetic devices.

In at least some embodiments, all of the steps of method 200 may beperformed or carried out by an appropriately or suitably configuredsystem, for example and without limitation, the system 20 describedabove, either alone or in conjunction with input from a user (e.g.,physician). In other embodiments, however, some of the steps may beperformed or carried out by different systems such that certain stepsmay be performed by one system (e.g., system 20), and other steps may beperformed by one or more other suitable systems. For purposes ofillustration, the description below will be primarily with respect to anembodiment wherein the method 200 is performed by the system 20described above either alone or in conjunction with user input. It willbe appreciated, however, that the present disclosure is not limited tosuch an embodiment. Additionally, it will be appreciated that unlessotherwise noted, the performance of method 200 is not meant to belimited to any one particular order or sequence of steps, or to anyparticular component(s) for performing the steps.

In an embodiment, method 200 comprises a step 202 of acquiring one ormore depictions of an anatomical region of interest of the patient'sbody that includes the structure of interest, and wherein each of theone or more depictions shows the structure of interest, the blood poolvolume of the LVOT of the patient's heart, or both. In an embodiment,the one or more depictions comprise one or more images each showing atleast a portion of the anatomical region of interest. These images maybe obtained from a memory device, for example, the memory device 30 ofthe system 20. Alternatively, the images may be acquired by generatingthem from image data, for example and without limitation, CT image data.While CT image data is specifically identified herein, it iscontemplated that image data corresponding to imaging modalities otherthan CT, such as, for example, one or more of those modalitiesidentified elsewhere above, may be used in addition to or instead of CTimage data.

In any event, in an embodiment, step 202 may comprise obtaining athree-dimensional digital imaging and communications in medicine (dicom)dataset corresponding to the anatomical region of interest. This datasetmay be processed using a multi-planar reformatting (MPR) technique togenerate or obtain a set of 2D images or views along the sagittal,coronal and axial planes, and these images or views may then be used asdescribed below. For example, FIG. 14a depicts an acquired image of theanatomic region of interest taken along the sagittal plane and showing,among other things, the cross-sectional surface area of the blood poolvolume of the LVOT, represented by reference numeral 68 in FIG. 14a .Plane indicators 70, 72 representing the axial and coronal planes,respectively, are also shown in FIG. 14a . FIG. 14b depicts an acquiredimage of the same anatomical region of interest shown in FIG. 14a takenalong the coronal plane and showing, among other structures, the leftatrium 74, the left ventricle 76, the LVOT 78, the aorta 80, and thestructure of interest 82, which, in this instance, is the patient'snative mitral valve. Plane indicators 70, 84 representing the axial andsagittal planes are also shown. In this particular embodiment, invertedmaximal intensity projection imaging is used to generate the images inFIGS. 14a and 14b so as to render the blood pool volume in each cardiacstructure dark and the surrounding tissue light to better delineate theclear intersections of the blood pool volume of, for example, the LVOT.In any event, image data and images corresponding thereto may beacquired for both the diastolic and systolic phases of the patient'scardiac cycle.

Once the depictions (i.e., images) are acquired in step 202, method 200may proceed to a step 204 of determining an unobstructed cross-sectionalsurface area of the blood pool volume of the LVOT. This surface area isconsidered to be unobstructed because no prosthetic valve models orrepresentations have been imported into, or hypothetical valve positionsdesignated in, the acquired image(s), and as such, the LVOT iseffectively “unobstructed” by a prosthetic valve model. In anembodiment, a sagittal view of the anatomical region of interest showingthe cross-section of the LVOT blood pool volume may be used to determinethis unobstructed cross-sectional surface area. Step 204 may beperformed automatically by, for example, the ECU 22 of the system 20.Alternatively, step 204 may be performed by the ECU 22 in conjunctionwith one or more user inputs made through the user interface device(s)26 of the system 20. For example, an image such as that shown in FIG.14a may be displayed on the display device 24 of the system 20 and auser may use the user interface device(s) 26 to outline or select theportion of the image corresponding to the cross-section of the LVOTblood pool volume (represented by reference numeral 68 In FIG. 14a ).Accordingly, it will be appreciated that the first cross-sectionalsurface area of the LVOT blood pool volume may be determined in a numberof ways, and as such, the present disclosure is not intended to belimited to any particular way(s) of doing so. In any event, as will bedescribed in greater detail below, this first cross-sectional surfacearea may be used in a subsequent step of method 200.

Following step 202 and, in at least some embodiments, step 202 and step204, method 200 may comprise a step 206 of designating one or morepositions in at least one of the acquired depictions (e.g., images)showing the structure of interest, wherein each designated positioncorresponds to a respective position or location in the structure ofinterest at which the prosthetic valve may be placed. In an embodiment,step 206 may comprise importing one or more models or otherrepresentations of the prosthetic valve into the at least one of theacquired images, and placing each of the one or more imported model(s)at respective positions within the structure of interest shown in theimage(s). In another embodiment, step 206 may comprise a user manuallydrawing or tracing a position that a portion of prosthetic valve mayassume within the structure of interest on one or more of the acquiredimages. For example, FIG. 14b illustrates a designation orrepresentation 86 representing a portion of the frame of a prostheticvalve, wherein the designation 86 is inserted into area of the imagecorresponding to the mitral annulus of patient's heart, and extendinginto the LVOT. In any event, it will be appreciated that the presentdisclosure is not intended to be limited to any particular way ofdesignating position(s) in the acquired image(s), but rather anysuitable way may be used.

Following step 206, method 200 may proceed to step 208 of predicting,for each of the one or more designated positions, an amount of bloodflow obstruction through the LVOT of the patient's heart that wouldoccur if the prosthetic valve was to be placed at a position in thestructure of interest that corresponds to the position designated in theat least one of the one or more acquired images. In an embodiment, step208 may comprise a number of substeps.

For example, in an illustrative embodiment, step 208 may comprise asubstep 210 of aligning both the axial and sagittal plane indicators inthe image taken along the coronal plane with a point at which a portionof the designated position of the prosthetic valve intersects the LVOTblood pool volume. In an embodiment, this point may correspond to thefurthest point into the blood pool volume that the valve modeldesignation reaches. For example, as shown in FIG. 14b , the axial planeindicator 70 and the sagittal plane indicator 84 are both aligned withthe end of the valve position designation 86 that is the furthest awayfrom the mitral annulus, and disposed the furthest into the LVOT. In anembodiment, once the axial and sagittal plane indicators are aligned,substep 210 may further comprise angling the intersection of the planeindictors such that the axial plane indicator 70 is parallel to alongitudinal axis 88 of the LVOT extending between the left ventricleand the aorta, and the sagittal plane indicator 84 is perpendicular tothe opposite basal anteroseptal wall 90 of the left ventricle. Anillustration of this is shown in FIG. 14b . Thereafter, in anembodiment, the intersection, and therefore the plane indicators, may beangulated to obtain the smallest LVOT surface area. The amount by whichthe plane indicators are angulated will be patient specific and will bebased on, for example, the angulation of the patient's anteroseptalwall. For purposes of this disclosure, the term “parallel” in thecontext of orienting the axial plane indicator with the longitudinalaxis of the LVOT is intended to include instances where the planeindicator is exactly parallel with the longitudinal axis, as well asinstances where the plane indicator is not exactly parallel but isnonetheless within a particular tolerance deemed suitable or acceptableby those of ordinary skill in the art for accurately performing themethodologies described herein (e.g., 0-10 degrees relative to theaxis). Similarly, for purposes of this disclosure, the term“perpendicular” in the context of orienting the sagittal plane indicatorwith the opposite basal anteroseptal wall is intended to includeinstances where the plane indicator is exactly perpendicular with theanteroseptal wall, as well as instances where the plane indicator is notexactly perpendicular but is nonetheless within a particular tolerancedeemed suitable or acceptable by those of ordinary skill in the art foraccurately performing the methodologies described herein. (e.g., 0-10degrees relative to a plane that is exactly perpendicular to theanteroseptal wall).

In an embodiment, substep 210 may be performed automatically by the ECU22 of the system 20; while in other embodiments, it may be performed bythe ECU 22 in conjunction with input provided by the user using, forexample, the user interface device(s) 26. Accordingly, the presentdisclosure is not intended to be limited any particular way(s) ofperforming substep 210.

Following the alignment of the plane indicators with the positiondesignation in substep 210, step 208 may comprise a further substep 212of determining a cross-sectional surface area of the blood pool volumeof the LVOT that remains or is preserved following the designation ofone or more valve positions in step 208. In other words, substep 212comprises determining an “obstructed” cross-sectional surface area ofthe LVOT blood pool volume. In an embodiment, an image of the anatomicalregion of interest taken along the sagittal plane and showing thecross-section of the LVOT blood pool volume along with an axial planeindicator oriented consistent with the position and orientation of theaxial plane indicator that was aligned in the image taken along thecoronal plane in substep 210 may be used to determine the obstructedsurface area.

For example, FIG. 14c depicts an image of the anatomic region ofinterest taken along the sagittal plane and showing, among other things,the cross-sectional surface area of the blood pool volume of the LVOT,and having the axial plane indicator 70 oriented consistent with theposition and orientation of the axial plane indicator 70 in FIG. 14b .In such an embodiment, the preserved or unobstructed cross-sectionalarea of the LVOT blood pool volume may be determined by calculating thesurface area of the portion of the cross-sectional surface of the LVOTblood pool volume that is between the axial plane indicator 70, which isrepresentative of a designated position of a prosthetic valve, and thebasal anteroseptal. The area of interest is represented by referencenumeral 92 in FIG. 14c . As with one or more of the steps describedabove, substep 212 may be performed automatically by, for example, theECU 22 of the system 20. Alternatively, substep 212 may be performed bythe ECU 22 in conjunction with one or more user inputs made through theuser interface device(s) 26 of the system 20. For example, an image suchas that shown in FIG. 14c may be displayed on the display device 24 ofthe system 20 and a user may use the user interface device(s) 26 tooutline or select the portion of the image corresponding to thepreserved cross-sectional surface area of the LVOT blood pool volume(represented by reference numeral 92 in FIG. 14c ). Accordingly, it willbe appreciated that the preserved or obstructed cross-sectional surfacearea of the LVOT blood pool volume may be determined in a number ofways, and as such, the present disclosure is not intended to be limitedto any particular way(s) of doing so.

Once the obstructed cross-sectional surface area is determined insubstep 212, the obstruction of the blood flow through the LVOT causedby a prosthetic valve being placed in a corresponding position withinthe structure of interest can be predicted based at least in part on theobstructed cross-sectional surface area. In an embodiment, however, theobstruction is predicted based on both unobstructed cross-sectionalsurface area determined in step 204 and the preserved or obstructedcross-sectional surface area determined in substep 212 of step 208. Moreparticularly, in an embodiment, the obstructed surface area may besubtracted from the unobstructed surface area, and the result may bedivided by the unobstructed surface area. The result is a percentagerepresenting the amount of the LVOT that would be obstructed, and thus,the amount of blood flow obstruction through the LVOT that would becaused for a given valve position.

In any event, once an obstruction prediction for each relevant valveposition has been made in step 208, method 100 may proceed to a step 214of determining a position or location in the structure of interest atwhich to actually place the prosthetic device based at least in part ofthe predicted blood flow obstruction(s).

In an embodiment, once steps 202-214 have been performed for one of thediastolic and systolic phases of the cardiac cycle, method 200 may berepeated for other of the diastolic and systolic phases, and thepredictions from step 208 and/or determinations from step 214 may beused together to determine an optimal position (i.e., axial positionand/or orientation) to place a prosthetic for that particular patient.

It is to be understood that the foregoing is a description of one ormore embodiments of the invention. The invention is not limited to theparticular embodiment(s) disclosed herein, but rather is defined solelyby the claims below. Furthermore, the statements contained in theforegoing description relate to particular embodiments and are not to beconstrued as limitations on the scope of the invention or on thedefinition of terms used in the claims, except where a term or phrase isexpressly defined above. Various other embodiments and various changesand modifications to the disclosed embodiment(s) will become apparent tothose skilled in the art. All such other embodiments, changes, andmodifications are intended to come within the scope of the appendedclaims.

As used in this specification and claims, the terms “e.g.,” “forexample,” “for instance,” “such as,” and “like,” and the verbs“comprising,” “having,” “including,” and their other verb forms, whenused in conjunction with a listing of one or more components or otheritems, are each to be construed as open-ended, meaning that the listingis not to be considered as excluding other, additional components oritems. Other terms are to be construed using their broadest reasonablemeaning unless they are used in a context that requires a differentinterpretation.

1. A computer-implemented method for evaluating the placement of aprosthetic mitral heart valve in a structure of interest located in theheart of a patient, comprising: acquiring one or more depictions of ananatomical region of interest that includes the structure of interest,wherein each of the one or more depictions shows the structure ofinterest, the blood pool volume of the left ventricular outflow tract(LVOT) of the patient's heart, or both; designating one or morepositions in at least one of the one or more depictions wherein eachposition corresponds to a respective position in the structure ofinterest at which the prosthetic valve may be placed; and for each ofthe one or more designated positions, predicting an amount of blood flowobstruction through the LVOT of the patient's heart that Would occur ifthe prosthetic valve was to be placed at a corresponding position in thestructure of interest.
 2. The method of claim 1, wherein the one or moreacquired depictions comprise(s) one or more three-dimensional modelseach showing the structure of interest, the blood pool volume of theLVOT, or both.
 3. The method of claim 1, wherein the one or moreacquired depictions comprise(s) one or more multi-dimensional imageseach showing the structure of interest, the blood pool volume of theLVOT, or both.
 4. The method of claim 1, wherein the structure ofinterest is a previously-implanted prosthetic valve or mitral ring. 5.The method of claim 1, wherein the structure of interest is the nativemitral valve of the patient's heart.
 6. The method of claim 1, furthercomprising determining a position at which to place the prostheticdevice within the structure of interest based on the predicted bloodflow obstruction.
 7. The method of claim 1, wherein for a givendesignated position, the predicting step comprises determining across-sectional surface area of the blood flow volume following thedesignation of the given position, and predicting the blood flowobstruction through the LVOT based on the determined cross-sectionalsurface area.
 8. A computer-implemented method for evaluating theplacement of a prosthetic mitral heart valve in a structure of interestlocated in the heart of a patient, comprising: acquiring a depiction ofan anatomical region of interest that includes the structure ofinterest, wherein the depiction shows the structure of interest and theblood pool volume of the left ventricular outflow tract (LVOT) of thepatient's heart; importing one or more models of the prosthetic valveinto the acquired depiction of the structure of interest; and for eachof one or more positions of the one or more models of the prostheticvalve in the depiction of the structure of interest, predicting anamount of blood flow obstruction through the LVOT of the patient's heartthat would occur if the prosthetic valve was to be placed at acorresponding position in the structure of interest.
 9. The method ofclaim 8, wherein the acquired depiction comprises a three-dimensionalmodel showing the structure of interest and the blood pool volume. 10.The method of claim 8, comprising: defining a plane that contains theaortic annulus of the patient's heart (“the aortic plane”); offsetting arepresentation of the aortic plane to a point in the acquired depictionat which a portion of one of the one or more imported valve modelsintersects the blood pool volume; determining a cross-sectional area ofthe blood pool volume along the offset representation of the aorticplane; and predicting the obstruction of the blood flow through the LVOTbased on the determined cross-sectional area.
 11. The method of claim10, wherein before determining the cross-sectional area, the methodcomprises: defining a plane that contains the mitral annulus of thepatient's heart (“the mitral plane”); and sectioning the acquireddepiction along the mitral plane.
 12. The method of claim 10, whereinthe determined cross-sectional area is a first determinedcross-sectional area and the method further comprises: removing the oneor more imported valve models in the acquired depiction; determining asecond cross-sectional area of the blood pool volume along the offsetaortic plane; and predicting the obstruction of the blood flow throughthe LVOT based on the first and second determined cross-sectional areas.13. The method of claim 10, wherein the determined cross-sectional areais a first determined cross-sectional area and the acquired depiction isa first depiction, the method further comprising: duplicating the firstdepiction to create a second depiction of the anatomical region ofinterest that includes the structure of interest, wherein the seconddepiction shows the structure of interest and the blood pool volume ofthe LVOT of the patient's heart; removing the one or more imported valvemodels in the second depiction; determining a second cross-sectionalarea of the blood pool volume along the offset aortic plane; andpredicting the obstruction of the blood flow through the LVOT based onthe first and second determined cross-sectional areas.
 14. The method ofclaim 8, wherein the importing step comprises importing a plurality ofvalve models, and the method further comprises positioning each of theplurality of valve models at a respective position that is differentthan the position(s) of the other of the plurality of valve models, andfurther wherein the plurality of valve models are positioned andoriented such that the valve models are coaxially arranged.
 15. Themethod of claim 8, wherein the importing step comprises importing aplurality of valve models and the method further comprises positioningeach of the plurality of valve models at a respective position that isdifferent than the position(s) of the other of the plurality of valvemodels, and further wherein the plurality of valve models are positionedsuch that at least one of the plurality of valve models has an angularorientation different than that of one or more other of the plurality ofvalve models.
 16. The method of claim 8, further comprising determininga position at which to place the prosthetic valve in the structure ofinterest based on the predicted obstruction of the blood flow throughthe LVOT.
 17. A computer-implemented method for evaluating the placementof a prosthetic mitral heart valve in a structure of interest located inthe heart of a patient, comprising: acquiring a plurality of images ofan anatomical region of interest that includes the structure ofinterest, wherein each of the images shows the structure of interest,the blood pool volume of the left ventricular outflow tract (LVOT) ofthe patient's heart, or both; designating a position in at least one ofthe one or more images corresponding to a respective position in thestructure of interest at which the prosthetic valve may be placed; andpredicting an amount of blood flow obstruction through the LVOT of thepatient's heart that would occur if the prosthetic valve was to beplaced at a position in the structure of interest that corresponds tothe position designated in the at least one of the one or more acquiredimages.
 18. The method of claim 17, wherein a first of the plurality ofacquired images comprises a view of the anatomical region of interesttaken along a coronal plane and showing the structure of interest andthe blood pool volume of the LVOT, and further wherein the designatingstep comprises designating in the first image the position correspondingto a respective position in the structure of interest at which theprosthetic valve may be placed, the method further comprising aligningplane indicators corresponding to axial and sagittal planes with a pointin the first image at which a portion of the designated position of theprosthetic valve intersects the blood pool volume.
 19. The method ofclaim 18, wherein a second of the plurality of acquired images comprisesa view of the anatomical region of interest taken along a sagittal planeand showing a cross-section of the blood pool volume of the LVOT andhaving an axial plane indicator positioned and oriented consistent withthe position and orientation of the axial plane indicator in the firstimage following the aligning step, the method further comprising:determining the cross-sectional surface area of the portion of thesurface of the blood pool volume of the LVOT shown in the second imagebetween the axial plane indicator and the basal anteroseptal wall of thepatient's heart shown in the second image; and predicting the amount ofblood flow obstruction through the LVOT based in part on the determinedcross-sectional area.
 20. The method of claim 19, further comprisingangling the intersection of the axial and sagittal plane indicators inthe first image such that the axial plane indicator is parallel to theLVOT and the sagittal plane indicator is perpendicular to the oppositebasal anteroseptal wall of the left ventricle shown in the first image.21. The method of claim 17, further comprising determining a position atwhich to place the prosthetic valve in the structure of interest basedon the predicted obstruction of the blood flow through the LVOT.